<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    div{
      width: 100px;height: 100px;border: 1px solid red;
    }
    div:hover{
      /*通过外边距实现,会导致其它元素跟着动*/
      /*margin: 20px 0 0 20px;*/
      position: relative;/*设置相对定位*/
      /*通过top/bottom/left/right让元素相对于初始位置偏移*/
      top: 20px;
      left: 20px;

    }
  </style>
</head>
<body>
<div>div1</div>
<div>div2</div>
<div>div3</div>
</body>
</html>